【作者】 马剑平；

【导师】 陈治明；

【作者基本信息】 西安理工大学 ， 微电子学与固体电子学， 2002， 博士

【摘要】 β碳化硅是碳化硅近200种不同结晶形态中唯一的纯立方结构晶体，载流子迁移率高，电子饱和漂移速度大，更适合于制造电子器件特别是电力电子器件之用。本文探索β碳化硅晶体生长技术的若干基本问题，特别对热系统的设计和热场分布问题，以及用β-SiC薄膜在碳饱和硅熔体中进行液相外延生长的基本工艺问题等进行了研究，获得以下主要创新结果： 1．通过对碳化硅生长设备中石墨坩埚系统的径向组合传热问题的分析讨论，建立了系统热分析的理论模型，提出了绝热层设计的理论依据，解决了坩埚组件热系统的设计问题并设计制作了实际应用的石墨坩埚组件系统。 2．采用有限元分析方法对线圈匝数、电流强度、电流频率等对焦耳热产生速率的影响进行了详细的分析讨论；采用不同的热辐射分析策略，对不同坩埚形状、坩埚顶部开设不同深度的盲孔以及线圈的位置等对热场分布的影响进行了数值分析，解决了感应加热碳化硅晶体生长系统热场设计的主要问题，提出了通过绝热层与盲孔的联合设计获得所需热场设计的思路，给出了根据轴向温度梯度的波动对线圈位置实行动态调节以控制热场的理论依据。 3．对利用硅衬底上的β-SiC薄膜从碳饱和硅熔体中外延生长β-SiC晶体的创新方法进行了工艺探索，介绍了基本工艺参数的获取过程和几个关键工艺问题的解决方法，特别是提出了通过工艺条件的调控来有效抑制6H-SiC等α型同质异构体在β-SiC生长过程中成核生长的工艺方案。 4．对实验样品进行了初步的结构特征分析和特性分析，在样品的Raman测试谱中发现了二级Raman散射的证据；利用硅衬底上的β-SiC薄膜从碳饱和硅熔体中外延生长出这β-SiC晶体。更多还原

【Abstract】 As the only one among nearly 200 polytypes of different crystalline SiC, which has a cubic crystalline structure, p-SiC is an excellent candidate for fabrication of high power devices because of its high values of saturated electron drift velocity and electron mobility in comparison with the other SiC polytypes. In this thesis, some fundamental topics on p-SiC crystal growth such as the design of the crucible assembling system, the thermal field distribution and the liquid phase epitaxial growth of p-SiC films deposited on Si have been discussed. In brief, following major creative results have been obtained:1. A theoretical model for analyzing thermal system has been established via the analysis and discussion of the radial combining heat transferring in the graphic crucible system. Based on the model, a theoretical equation for designing the thermo-insulator and a design solution of the crucible assembling system has been suggested. Whereby, the designing problem in the heating system of crucible components is solved, and the graphic crucible component system in practical application is designed and manufactured.2. The finite element method (FE’.I) is adopted to analyze the effects of the numbers of coil turns, current intensity and current frequency upon the rate of joule heat generation in details. The thermo-radiation analytical countermeasures of various types are adopted to carry out the numerical analysis of the effects of the crucible with different shapes and sizes and the blind holes with different depths opened in the tops of crucibles as well as coil positions upon the thermal field distribution whereby solving the main problem of field the thermo-field design of the induction-heating SiC crystal growth system. A New combination idea of the thermo-field design obtained by means of the united design of the thermo-insulator and blind holes has been presented. The theoretical basis of the dynamic adjusting of coil positions for controlling over the thermo-fields based on the fluctuation effect of axial temperature gradient is suggested.3. The novel method of liquid phase epitaxial growth process of p-SiC from p-SiC film on Si substrate in C-saturated Si solvent is further investigated. Some processes of acquiring the fundamental technical parameters and some solution to some critical technical problems are introduced. Especially, the optimized technical schemes of effectively restraining such a-SiC polytypes as GH-SiC coring and growing in p-SiC epitaxial growth process is presented.4. The structural characteristics of the samples are analyzed. Much discussion on Roman spectroscopy of the samples is made in details, and the second-order scattering lines of SiC are found. The p-SiC crystal has been successfully grown from its thin film deposited on Si substrate.更多还原